Heating element CVD system

ABSTRACT

A heating element CVD device capable of providing a high productivity and decomposing and/or activating the material gas led into a processing container by a heating element and stacking film on a substrate disposed in the processing container, wherein the connection part area of the heating element to a connection terminal for connecting the hearing element to a power supply mechanism is not exposed to a space inside the processing container, specifically, the connection part area is covered by a cylindrical body or a platy body covering the connection part area while providing a space part thereof from the hearing element, or the connection part area allows the space part to be present in a space thereof from the connection terminal and is covered by the cylindrical body or platy body covering the connection part area while providing the space part in a space thereof from the heating element, and hydrogen gas is led from the connection terminal side into the processing container through the space part, whereby the portion of the heating element near the connection part to the power supply mechanism can be prevented from being deteriorated by the material gas, the material gas can be prevented from reacting with cleaning gas during the cleaning for removing the film adhered to the inside of the processing container, the service life of the heating element can be increased, and a film forming environment can be stabilized.

TECHNICAL FIELD

The present invention relates to a heating element CVD system in which aheating element kept at a specified temperature is disposed in a vacuumchamber (processing container) and in which a raw material gas isdecomposed and/or activated by the said heating element to deposit athin film on a substrate placed in the vacuum chamber (processingcontainer).

BACKGROUND ART

In manufacturing various kinds of semiconductor devices including a LSI(large scale integrated circuit), a LCD (liquid crystal display) and thelike, a CVD (chemical vapor deposition) method has been widely used asone process for forming a predetermined thin film on a substrate

In CVD method, there are several methods, that is, a plasma CVD methodin which a raw material gas is decomposed and/or activated in dischargedplasma to form a thin film, a thermal CVD method in which a substrate isheated to induce a chemical reaction to form a thin film and so on. Inaddition, a CVD method in which a raw material gas is decomposed and/oractivated by a heating element kept at a predetermined high temperatureto form a thin film (hereinafter referred to as a heating element CVDmethod).

In a film forming system for performing the heating element CVD method(hereinafter referred to as a heating element CVD system), a heatingelement made of a refractory metal such as tungsten or the like isdisposed in a processing chamber. The processing chamber is capable ofbeing evacuated to a vacuum. A raw material gas is introduced into theevacuated processing chamber while the heating element is kept at hightemperatures from about 1000° C. to 2000° C.

The introduced raw material gas is decomposed and/or activated when itpasses over the surface of the heating element and reaches a substrateto deposit a thin film of the material, which is a final objectivematerial, on the surface of the substrate. In the heating element CVDmethods, a CVD method using a wire-shaped heating element is called as aHot Wire CVD method, and a CVD method utilizing the catalytic reactionof a heating element for decomposing and/or activating the raw materialgas is called as a catalytic CVD (or Cat-CVD) method.

In the heating element CVD method, the raw material gas is decomposedand/or activated when it passes over the surface of the heating element.For this reason, this method has an advantage of reducing thetemperature of the substrate as compared with the thermal CVD method inwhich reaction is induced only by the heat of the substrate. Further, inthe heating element CVD method, plasma is not produced, as it isproduced in the plasma CVD method. For this reason, there is no worrythat plasma causes damage to the substrate. Accordingly, the heatingelement CVD method is thought to be a promising candidate as a filmforming method for a semiconductor device, a display device and the likeof the next generation in which high integration and high functionalityhave been increasingly required.

FIG. 10 shows conceptional view of a conventional heating element CVDsystem. In a processing container 1, a predetermined processing offorming a thin film is performed to a substrate (not shown). Anevacuation system 11 for evacuating the processing container 1 to avacuum and a raw material gas supply system 21 for supplying a rawmaterial gas into the processing container 1 for forming a thin film areconnected to the processing container 1.

In the processing container 1, a heating element 3 is disposed such thatthe raw material gas supplied into the processing container 1 passesover the surface of it. A power supply mechanism 30 for supplyingelectric power is connected to the heating element 3, thereby theheating element 3 is heated and kept at a predetermined temperature (ahigh temperature of about from 1600° C. to 2000° C.) required for theheating element CVD method. Further, in the processing container 1, agas supply unit 2 and the heating element 3 are arranged facing eachother.

Further, in the processing container 1, a predetermined thin film isformed on the substrate (not shown) by the raw material gas decomposedand/or activated by the heating element 3 that is kept at thepredetermined high temperature described above. For this reason, in theprocessing container 1, a substrate holder 4 is provided for holding theabove-mentioned substrate (not shown).

In FIG. 10, it is a gate valve for carrying the substrate into or out ofthe processing container 1 that is denoted by a reference character 5.Further, the substrate holder 4 is provided with, as is conventionallyknown, a heating mechanism for heating the substrate, but this heatingmechanism will not be shown or described because it is not important inthe present invention.

In the embodiment shown in FIG. 10, although it is not shown, the rawmaterial gas supply system 21 includes a cylinder filled with the rawmaterial gas, a supply pressure regulator, a flow regulator, asupply/stop switching valve, and the like. The raw material gas issupplied by the raw material gas supply system 21 into the processingcontainer 1 via the gas supply unit 2 provided in the processingcontainer 1.

Further, in a process using two or more kinds of raw material gases, theraw material gas supply systems 21 of the number equal to the number ofkinds of gases used are connected in parallel to the gas supply unit 2.

The gas supply unit 2, as described above, is arranged in face with theheating element 3 in the processing container 1. Further, the gas supplyunit 2 has a hollow structure and many gas blowing holes 210 on asurface facing the substrate holder 4.

On the other hand, the evacuation system 11 is connected to theprocessing container 1 via a main valve 12 having an evacuation speedregulating function. The pressure of the processing container 1 iscontrolled by this evacuation speed regulating function.

In the heating element CVD method, the substrate (not shown) is asubstance to be subjected to a predetermined processing of forming athin film. This substrate (not shown) is carried in and out of theprocessing container 1 via the gate valve 5. And a heating mechanism(not shown) for heating the substrate (not shown) to a predeterminedtemperature is built in the substrate holder 4.

The heating element 3 is generally formed of a wire-shaped member and isbent in the shape of sawteeth and is held by a support body 31, thesurface of which is at least made of insulator. Further, a power supplyline 32 from the power supply mechanism 30 is connected to the heatingelement 3 by a connection terminal 33. An electric power is supplied tothe heating element 3 via this connection terminal 33 to heat theheating element 3 to the predetermined temperature required for theheating element CVD method and to keep it at the predeterminedtemperature.

Usually, a direct current power source or an alternating current powersource is used as the power supply mechanism 30. The heating element 3is supplied with electric power from the power source and is set at thepredetermined temperature by the passage of the electric current. Byheating the heating element 3 to a high temperature, the raw materialgas is decomposed and/or activated to effectively form a thin film.

Usually, the heating element 3 is heated to a predetermined temperature(usually, at a film forming process, a high temperature of from about1600° C. to 2000° C.) by the passage of the electric current, so arefractory metal is used as the material for the heating element 3 and,in general, tungsten is used.

A case where a silicon film is formed and a case where silicon nitridefilm is formed are explained as examples of forming a thin film by theheating element CVD system shown in FIG. 10. The processes are proceededas follows.

First, a mixed gas of silane (SiH₄) and hydrogen (H₂) is used in thecase where the silicon film is formed. A mixed gas of silane and ammonia(NH₃) is used in the case where the silicon nitride film is formed. Thepressure in the processing container 1 is about from 0.1 Pa to 100 Pa.In both cases, the temperature of the heating element 3 is set at apredetermined temperature (usually, a high temperature of about from1600° C. to 2000° C. at a film forming process), and the temperature ofthe substrate (not shown) held by the substrate holder 4 is set at atemperature of about from 200° C. to 500° C. by a heating mechanism (notshown) in the substrate holder 4.

In the case where the silicon film or the silicon nitride film is formedunder predetermined film forming conditions by the use of a conventionalheating element CVD system described above, the following phenomenon isproduced. A refractory metal used for the heating element, for example,a tungsten wire described above or the like sometimes reacts with thesilane gas to form a silicon compound (hereinafter referred tosilicidation).

A silicidation mentioned above proceeds from near a connection terminal33 that is the connection part by which electric power is supplied fromthe power supply mechanism 30 (that is, the connection region of theheating element 3). In the said connection region of the heating element3, the temperature becomes lower than 1600° C. even at the film formingprocess. Further, in the said connection region of the heating element3, the reaction speed of the raw material gas with the heating element 3is faster than the desorption speed of decomposed and/or activated gasspecies of the raw material gas and raw material gas itself.

The above-mentioned silicidateion changes the composition and diameterof the heating element 3 and reduces the resistance thereof. As aresult, the heating power is reduced and the whole heating element isfinally deteriorated. Also, it reduces a film forming speed as hours ofuse of the heating element is elongated. Further, since the products ofthe silicide and the like have high vapor pressures in general, theycontaminate the deposited film and degrade the quality of the siliconfilm formed or the silicon nitride film formed as the deterioration ofheating element is proceeding.

Therefore, it is necessary to break the vacuum in the processingcontainer 1 to the atmospheric pressure and to change the heatingelement 3 when a predetermined number of substrates are processed. Thischange of the heating element 3 results in a problem in productivity.

As to this silicidation phenomenon, A. H. Mahan et al. made apresentation of a detailed paper entitled “The influence of W filamentalloying on the electronic properties of HWCVD deposited a-Si:H films”in Materials Research Society 2000 Spring Meeting held at Marriott Hoteland Argent Hotel in San Francisco in the U.S.A. from Apr. 24 to 28,2000.

As to means for controlling the deterioration caused by the silicidationof the heating element, Mahan et al. proposed means for elongating thelife of the heating element in the paper, that is, heating the heatingelement in a hydrogen gas or in a vacuum after forming a film.

However, this means needs to secure a time for performing the processingbetween the formations of the respective films and hence results in aproblem of reducing productivity. Further, to be exact, the silicidationof the heating element proceeds while the film is being formed, that is,the temperature of the heating element or a film forming environmentaround the heating element 3 such as the effective region of the heatingelement 3 for the decomposition and/or activation of the raw materialgas and the like is changed while the film is being formed. For thisreason, the characteristics of the film is changed (degraded) in thedirection of thickness in the case when the film forming time is long.

FIG. 11 is a view to show a part of a support body 31 of a conventionalembodiment. In the part of a support body 31 of the conventionalembodiment, the heating element 3 is supported by the support body 31 bymeans of a wire 34 (usually, made of molybdenum) to reduce a contactarea of the heating element 3 thereby reducing thermal conduction. Theconventional embodiment shown in FIG. 11 is intending to preventsilicidation, which proceeds from the portion of the heating element 3where its temperature is slightly low.

However, even in this method, the temperature of the heating element 3at the portion in contact with the wire 34 drops inevitably, so that thesilicidation at and from the said portion is caused, depending on filmforming conditions such as a high silane gas pressure in case of formingthe silicon film or the like.

Further, even in this method, it is impossible to eliminate connectionto the power supply line 32, so that the silicidation is also caused atthe portion of the connection terminal 33 as is the case shown in FIG.10.

Therefore, even in a heating element CVD system adopting theconstitution shown in FIG. 11, it is necessary to break the vacuum inthe processing container 1 to the atmospheric pressure and to change theheating element 3 when a predetermined number of substrates areprocessed. The change of the heating element 3 results in a problem inproductivity.

By the way, if films are repeatedly formed in the heating element CVDsystem, the films are deposited on the inside of the processingcontainer and are peeled off and results in the cause of the particulateproblem. The inventors of the present application proposed a method ofeffectively removing a film deposited on the inside of a processingcontainer, which become an origin of particulates, and an in situcleaning method of a heating element CVD system (Japanese PatentApplication Laid-Open (JP-A) No. 2001-49436).

According to this method, a gas supply unit 2 of a conventional heatingelement CVD system shown in FIG. 10 is provided with a cleaning gassupply system having the same constitution as a raw material gas supplysystem 21, and when cleaning the system, instead of a raw material gasused in forming a film, a cleaning gas is introduced into a processingcontainer 1 via the gas supply unit 2. That is, this is an inventioncharacterized in that after the processing container 1 is evacuated, aheating element 3 disposed in the processing container 1 is heated toand kept at a temperature of 2000° C. or more, and that a cleaning gaswhich is decomposed and or activated by the heated body 3 to produceactivated species which in turn react with a deposited film to change itinto a gaseous substance is introduced into the processing container 1,and that the produced gaseous substance is exhausted from the processingcontainer 1 to remove the deposited film from the inside surface ofprocessing chamber. This invention has been made based on findings thatwhen the heating element 3 is kept at a temperature of 2000° C. or more,the heating element 3 itself does not react with the cleaning gas butremains stable.

However, after the above-mentioned invention was made, it turned outthat even if it was tried to keep the heating element 3 at a temperatureof 2000° C. or more, a part near the connection terminal 33, which isthe connection part of power supply from a power supply mechanism 30 tothe heating element 3, was low in temperature, and that the said partwas etched by the cleaning gas and was gradually reduced in diameter andfinally broken by the reaction of the said part with the cleaning gas.Thus, it is necessary to replace the heating element at a certain time,which results in a problem in productivity.

Further, it was found that in the case where a film was deposited on alarge-area substrate of over 1 m by the use of a heating element CVDsystem shown in FIG. 10 and FIG. 11, there was a room for improvement inthe uniformity of thickness of a thin film deposited.

In the Cat-CVD method, in the case where in order to form a film on alarge-area substrate by the use of the heating element CVD system shownin FIG. 10 and FIG. 11, a conventional technique is adopted in which asawtooth heating element 3 is supported by a large size support frame aslarge as a substrate, there is presented a problem that the heatingelement 3 is drooped by thermal expansion. That is, since the sawtoothheating element 3 is thermally expanded by about 1% when it is heated to1800° C., if a heating element 3 having a length of 1 m is used to forma film on a large-area substrate, the heating element 3 is drooped by 70mm at the maximum by a thermal expansion of 1%. In the worst case, it isestimated that the heating element 3 is drooped more than the distancebetween the substrate and the heating element 3, which is usually set atabout 50 mm. According to the inventor's study, it is verified that thegap (distance) between the heated heating element 3 and the substratesubjected to a film forming process greatly affects the uniformity of afilm thickness when the film is formed.

At present, it is prospected that the size of a next-generation glasssubstrate is larger than 1 m. For example, it is planned to use a largesubstrate of 1100 mm×1250 mm for a LCD and 1000 mm×400 mm for a solarcell. In order to form a film on such a large-area substrate, it isnecessary to reduce the degree of drooping of the heating element 3caused by the thermal expansion mentioned above and to ensure theuniformity of thickness of the film formed on the large-area substrate,so that the heating element CVD system shown in FIG. 10 and FIG. 11 hasa room for improvement.

DISCLOSURE OF THE INVENTION

In a heating element CVD system in which a raw material gas introducedinto a processing container (vacuum chamber) is decomposed and/oractivated by a heating element to deposit a thin film on a substrateplaced in the processing container (vacuum chamber), the objects of thepresent invention are as follows: one object is to prevent theconnection region of the heating element connected to a power supplymechanism from being degraded by the raw material gas; and anotherobject is to prevent the connection region of the heating elementconnected to a power supply mechanism from reacting with a cleaning gaswhen a cleaning process for removing a film deposited on the inside ofthe processing container is proceeded.

By countermeasures mentioned above, it is the object of the presentinvention to provide a heating element CVD system having highproductivity that can elongate the life of the heating element andrealize a stable film forming environment.

Further, it is the object of the present invention to provide a heatingelement CVD system that can meet with a film forming on a large-areasubstrate having a size of im or more and can ensure a uniform filmthickness even if the film is formed on such a large-area substrate.

A heating element CVD system of the present invention is constituted asfollows in order to accomplish the above objects.

A heating element CVD system of the present invention is provided with aprocessing container in which a predetermined processing is performed toa substrate held by a substrate holder disposed therein, an evacuationsystem which is connected to the said processing container and evacuatesit to a vacuum, a raw material gas supply system for supplying apredetermined raw material gas into the said processing container, and aheating element which is disposed in the said processing container andis supplied with electric power from a power supply mechanism and isthereby heated to high temperatures (about from 1600° C. to 2000° C.when a film is formed and about 2000° C. to 2500° C. when a cleaningprocess is performed). And the heating element CVD system of the presentinvention relates to a heating element CVD system in which the rawmaterial gas introduced into the processing container from the rawmaterial gas supply system is decomposed and/or activated by the heatingelement kept at the high temperatures to deposit a thin film on thesubstrate held by the substrate holder,

In this connection, the predetermined processing described above means,for example, depositing a thin film on the substrate to be processed,which is placed in the processing container, and a cleaning or removingthe substance deposited on the inside of the processing container.Further, the predetermined raw material gas is determined variouslyaccording to the thin film to be deposited and, for example, in the caseof depositing a silicon film, a mixed gas of silane (SiH₄) and hydrogen(H₂) is used as the predetermined raw material gas described above, andin the case of depositing a silicon nitride film, a mixed gas of silaneand an ammonia (NH₃) is used as the predetermined raw material gasdescribed above.

The heating element CVD system of the present invention is characterizedin that, in the configuration as the before described, one or aplurality of connection terminal holders is placed in the processingchamber. Each of the said connection terminal holders holds a pluralityof connection terminals at a predetermined position with electricallyinsulating therebetween. Each of the said connection terminals connectsthe heating elements to the power supply mechanism electrically. Thesaid heating elements connected to the connection terminals aresupported in face with the substrate holder. And, in that, a connectionregions of the heating elements connected to the said connectionterminals are not exposed to a space in the processing container.

Each connection terminal holder in the above-described heating elementCVD system of the present invention is a structure that is independentof the processing container and can be removed from the processingcontainer. Further, each connection terminal holder is connected to thepower supply mechanism, the raw material gas supply system, and a gasintroduction system which will be described later, respectively

In the case where a substrate to be processed is not particularly largein size, it is good enough to place one connection terminal holder inthe processing container, but in the case where a substrate to beprocessed has a large area of 1 m or more, it is possible to cope withsuch a large-area substrate by increasing the number of connectionterminal holders to be placed in the processing container. That is, evenif the substrate to be processed has a large area of 1 m or more, it ispossible to eliminate the need for manufacturing a single connectionterminal holder that is equal to or larger than the area of thesubstrate to be processed. On the contrary, it is possible to circumventsuch restriction on the arrangement of the heating element that isrestricted according to the shape and size of a supporting body in theconventional art. Further, it is possible to arrange the heating elementat any position of the connection terminal holder and to make a wireshaped heating element suitable length, in each connection terminalholder. For this reason, it is possible to reduce the degree of droopingof the heating element caused by thermal expansion.

In the above description, one or a plurality of connection terminalholders is placed in the processing chamber. Each of the said connectionterminal holders holds a plurality of connection terminals at apredetermined position with electrically insulating therebetween. Eachof the said connection terminals connects the heating elements to thepower supply mechanism electrically. The said heating elements connectedto the connection terminals are supported in face with the substrateholder. By the use of the said connection terminal holder, it ispossible to arrange the heating elements adequately at more preferableposition, and thus to form a thin film having a uniform film thickness.

In particular, even in the case where a plurality of connection terminalholders are disposed to form a thin film on a large-area substratehaving a size of 1 m or more, it is possible to form the thin filmhaving a uniform film thickness on the large-area substrate. This isbecause it is possible to suitably arrange the heating elements at amore preferable positions in accordance with an area of substrate to beprocessed, process condition, or the like in order to improve theuniformity of the thin film at the boundary region between theneighboring connection terminal holders and at the peripheral portion ofthe large-area substrate.

Further, even in the case where a film is formed on the large-areasubstrate having a size of 1 m or more, it is only necessary to disposea plurality of connection terminal holders each of which is anindependent structure, as described above. For this reason, it ispossible to manufacture one connection terminal holder at low cost insuch a size as improves workability and is easy to machine. Even if asubstrate on which a film is formed is large in size, it is possible toeasily form the film on such large-area substrate by arranging theplurality of connection terminal holders. Further, it is possible toimprove the work efficiency of maintenance such as dismounting ormounting the connection terminal holders for repair in the processingcontainer.

Next, in the heating element CVD system of the present invention, asdescribed above, the connection region of the heating element connectedto the connection terminal to connect the heating element to the powersupply mechanism electrically is not exposed to the space in theprocessing container. Thus, it is possible to prevent the raw materialgas such as silane or the like from contacting a region of the heatingelement where temperature is slightly low (the connection region of theheating element connected to the connection terminal) This can preventthe region of the heating element where temperature is slightly low frombeing degraded (changed to a silicide) by the raw material gas when thefilm is formed.

The structure for preventing the connection region of the heatingelement to the connection terminal from being exposed to the space inthe processing container can be realized, for example, by the preferredembodiment described in the following.

In the first preferred embodiment, the connection region of the heatingelement to the connection terminal is covered with a cylindrical body ora plate which is made of an insulating substance, a metal, or acomposite of these materials and covers the said connection region witha gap between the cylindrical body or the plate and the heating element.

In the second preferred embodiment, the connection region of the heatingelement to the connection terminal is covered with a cylindrical body ora plate that is made of an insulating substance, a metal, or a compositeof these materials and covers the connection region with a connectionterminal inside hollow portion between the cylindrical body or the plateand the connection terminal and with a gap between the cylindrical bodyor the plate and the heating element.

In the third preferred embodiment, the connection terminal isconstituted by a connection terminal body and a cap put on the saidconnection terminal body with a gap between itself and the heatingelement, and a connection terminal inside hollow portion is formedbetween the cap and the connection terminal body.

In any one of the preferred embodiments described above, it is possibleto prevent the connection region of the heating element to theconnection terminal from being exposed to the space in the processingcontainer. Thereby, it is possible to prevent the connection region ofthe heating element (that is, the part of the heating element wheretemperature is slightly low) from contacting the raw material gas or theactivated species originated from the raw material gas when the film isformed and from contacting a cleaning gas when a cleaning process isperformed.

In this connection, in place of the cylindrical body, it is alsopossible to use a plate having a hole corresponding to the hollowportion of the cylindrical body and a thickness corresponding to thelength of the cylindrical body. And, it is possible to produce the sameworking and effect by using the said plate with covering the connectionregion of the heating element connected to the connection terminal andwithout contacting the heating element.

In the before described structure, as the hole of the cylindrical bodyor the plate is smaller in inside diameter and longer in length, theconnection region of the heating element can be prevented moreeffectively from being exposed to the space in the processing container.That is, it is preferable from the viewpoint of preventing theconnection region of the heating element from contacting the rawmaterial gas when the film is formed that the hole of the cylindricalbody or the plate is smaller in inside diameter and longer in length.Hence, in consideration of manufacturing accuracy and manufacturingcost, for example, in the case where a tungsten wire of 0.5 mm indiameter is used as a heating element, it is preferable that the insidediameter of the cylindrical body or the plate is about from 0.7 mm to3.5 mm and the length thereof is about from 10 mm to 50 mm.

The above-described cylindrical body or plate is heated at a hightemperature by the radiation from the heating element. Hence, it isdesired that the above-described cylindrical body or plate is formed ofa material having as low a vapor pressure as possible, for example, arefractory metal such as tantalum, molybdenum or aluminum. Further, itis thought that the above-described cylindrical body or plate is made ofa metallic material and is directly attached to a member (for example, aplate) for holding a member to which the heating element is connected(for example, the connection terminal body or the like). In this case,there is a possibility that the said plate, etc. is put into contactwith the heating element by thermal strain and the like so as to developan electric short circuit. Hence, to prevent such electric shortcircuit, it is desirable that the above-described cylindrical body orplate is formed of a composite material covered with an insulatingmaterial such as aluminum or the like.

Further, it is possible to cover the connection region of the heatingelement to the connection terminal in the form without contacting withthe said connection region. That is, the connection region of theheating element to the connection terminal is covered with theabove-described cylindrical body or plate with a gap between theabove-described cylindrical body or plate and the connection terminaland with a gap between the above-described cylindrical body or plate andthe heating element. In this manner, it is possible to adopt a structurein which the connection region of the heating element to the connectionterminal is not exposed to the space in the processing container and inwhich a purge gas is flowed through the gap described above from theconnection terminal to the processing container.

Thereby, it is possible to further effectively prevent the connectionregion of the heating element where temperature is slightly low when thefilm is formed from being degraded (changed to a silicide) by the rawmaterial gas. Further, when the deposited film is removed (a cleaningprocess is performed), it is possible to further effectively prevent thepart of the heating element (connection region of the heating element)where temperature is slightly low from contacting and reacting with(being etched by) the cleaning gas.

This can be realized by adopting the following embodiment.

For example, each connection terminal holder has the first inside hollowportion, and the connection region of the heating element connected toeach of a plurality of connection terminals held at a predeterminedposition of the connection terminal holder in an electrically insulatedstate is covered with a cylindrical body or a plate made of aninsulating material or a metal or a composite material of thesematerials, which covers the said connection region of the heatingelement with the connection terminal inside hollow portion between thecylindrical body or the plate and the connection terminal and with a gaspassing hole between the cylindrical body or the plate and the heatingelement, and the connection terminal inside hollow portion communicateswith the said first inside hollow portion to which a gas supplyintroduction system for introducing gas is connected.

Alternatively, each connection terminal holder has the first insidehollow portion, and each of a plurality of connection terminals held ata predetermined position of the connection terminal holder in anelectrically insulated state is constituted by the connection terminalbody and a cap put on the said connection terminal body with a gaspassing hole between the cap and the heating element, and a connectionterminal inside hollow portion is formed between the cap and theconnection terminal body, and the connection terminal inside hollowportion communicates with the said first inside hollow portion to whicha gas supply introduction system for introducing gas is connected.

In any one of the preferred embodiments described above, the connectionterminal inside hollow portion communicates with the space in theprocessing container through the gas passing hole.

Therefore, the gas or the mixed gas (purge gas) introduced into the,first inside hollow portion of each connection terminal holder from thegas introduction system is introduced into the processing containerthrough the connection terminal inside hollow portion and the gaspassing hole.

Thereby, it is possible to prevent the raw material gas such as silanegas or the like or the activated species originated from the rawmaterial gas decomposed and/or activated on the surface of the heatingelement from entering into the connection terminal inside hollowportion. That is, it is possible to effectively prevent the raw materialgas or the like from contacting a portion of the heating element wheretemperature is slightly low (connection region of the heating element).Further, also when the deposited film is removed (the cleaning processis performed), it is possible to prevent the cleaning gas from enteringinto the connection terminal inside hollow portion. That is, it ispossible to effectively prevent the gas or the like from contacting theportion of the heating element where temperature is slightly low(connection region of the heating element).

In other words, thereby, it is possible to prevent the portion of theheating element where temperature is slightly low (connection region ofthe heating element to the connection terminal) from being degraded(changed to a silicide) by the raw material gas when the film is formedand from reacting with (being etched by) the cleaning gas when thedeposited film is removed (the cleaning process is performed).

Here, the above-described cylindrical body, plate, and cap are arrangedwithout contacting the heating element and the heating element issupported only by the connection terminal. Further, gas other than theraw material gas or the cleaning gas is flowed to eliminate the effectof reverse diffusion of the raw material gas. For this reason, it ispossible to prevent the heating element in its entirety from beingdegraded by the raw material gas and to realize a stable film formingenvironment when the film is formed, and to prevent the heating elementfrom reacting with the cleaning gas when the deposited film is removed(the cleaning process is formed).

As a result, the life of the heating element is elongated to reduce thedowntime of production, caused by maintenance, so that productivity canbe improved.

In this connection, in the above preferred embodiment, the cap may havea cylindrical body or a plate that mounted on the said cap and coversthe connection region of the heating element to the connection terminalwithout contacting the heating element, and is made of a insulatingmaterial or a metal or a composite material of these materials. This caninduce the working and effect produced by the configuration in which theconnection region of the heating element to the connection terminal iscovered with the cap that is mounted on the connection terminal body insuch a way as to form the connection terminal inside hollow portionbetween the cap and the connection terminal body and to produce the gap(for example, gas passing hole) between the cap and the heating element.Further, in addition, this can produce the same working and effectproduced by the above-described configuration that enables the gas orthe mixed gas introduced into the first inside hollow portion of theconnection terminal holder to be introduced into the processingcontainer through the connection terminal inside hollow portion, whichcommunicates with the first inside hollow portion, and the gas passinghole. Further, this can produce the working and effect produced by theconfiguration in which the cylindrical body or plate for covering theconnection region of the heating element to the connection terminalwithout contacting the heating element is mounted on the said cap. Thatis, these effects are overlapped. Therefore, it is possible to furthereffectively to prevent the portion of the heating element wheretemperature is slightly low (connection region of the heating element tothe connection terminal) from being degraded (changed to a silicide) bythe raw material gas when the film is formed, and from being etched bythe reaction with the cleaning gas when the deposited film is removed(the cleaning process is performed).

In this respect, in the above-described preferred embodiment, the gasintroduced toward the processing container from the side of theconnection terminal, that is, the gas introduced into the first insidehollow portion of the above-described respective connection terminalholders may be any one gas of hydrogen, argon, helium, neon, krypton,xenon, nitrogen, or ammonia, or a mixed gas of two or more kinds ofthese gases.

In the heating element CVD system in accordance with the presentinvention described above, a connection part between the connectionterminal and the power supply mechanism, or a connection part betweenthe connection terminal and the power supply mechanism and a wiring partfor electrically connecting the connection terminals may be built in theconnection terminal holder.

To be more specific, each connection terminal holder may have the firstinside hollow portion, and a connection part between the connectionterminal and the power supply mechanism, or a connection part betweenthe connection terminal and the power supply mechanism and a wiring partfor electrically connecting the connection terminals may be arranged inthe said first inside hollow portion.

This can prevent the connection part between the connection terminal andthe power supply mechanism, or the connection part between theconnection terminal and the power supply mechanism and the wiring partfor electrically connecting the connection terminals from being exposedto the space in the processing container. Therefore, this can preventthe possibility that these parts are degraded by the raw material gas,the species decomposed and/or activated on the surface of the heatingelement, originated from the raw material gas, or the cleaning gas.

Further, in the heating element CVD system in accordance with thepresent invention, each connection terminal holder may communicate withthe space in the processing container only through a plurality of gasblowing holes made in the surface on the side in face with the substrateholder, and may have the second inside hollow portion connected to theraw material gas supply system.

Thereby, the raw material gas is supplied from the raw material gassupply system to the processing container by introducing the rawmaterial gas firstly into the second inside hollow portion, and thenintroducing into the processing container through the plurality of gasblowing holes. Further, the cleaning gas is also supplied to theprocessing container by introducing the cleaning gas firstly into thesecond inside hollow portion, and then introducing into the processingcontainer through the plurality of gas blowing holes.

In this manner, the plurality of gas blowing holes for introducing theraw material gas and the like into the processing container and theheating elements form an integrated structure by the respectiveconnection terminal holders. This eliminates the need for the supportmember 31 used in the conventional heating element CVD system shown inFIG. 10 and FIG. 11. The support member 31 for supporting the heatingelement is the part on which the film might be deposited. Thus, theelimination of the support member 31 can simplify a film forming regionaround the heating element and can form a film in a uniform thicknessand further improve productivity even when a large-area substrate isprocessed.

When a film is formed, a raw material gas is introduced into the secondinside hollow portions of the respective connection terminal holders,and when a cleaning process is performed, a cleaning gas is introducedinto the second inside hollow portions of the respective connectionterminal holders. According to the above-described structure, the firstinside hollow portion is separated from the second inside hollowportion, so that the portions where the connection terminals areconnected to the power supply mechanism and the connection wiringbetween the connection terminals are not exposed to the raw material gasand the cleaning gas in the structure.

That is, by adopting the above-mentioned structure, it is possible toprevent a connection part between the connection terminal and the powersupply mechanism, or a connection part between the connection terminaland the power supply mechanism and a wiring part for electricallyconnecting a connection terminals from being degraded by the rawmaterial gas existing in the space in the processing container, andfurther to prevent these portions, in the each respective connectionterminal holders, from contacting the raw material gas and the cleaninggas, supplied to each connection terminal holder in the respectiveconnection terminal holders and introduced into the processing containerthrough the plurality of gas blowing holes

Still further, in the above-described heating element CVD system inaccordance with the present invention, each connection terminal holdermay hold a plurality of heating elements such that they are in face withthe substrate holder, and the gap between at least one or more heatingelement of the plurality of heating elements and the connection terminalholder may be different from the gap between the other heating elementand the connection terminal holder.

In this manner, it is possible to adjust the distance between theheating element and the connection terminal holder by which the saidheating element is supported. That is, it is possible to adjust thedistance or the gap between the substrate on which the film is to bedeposited and the heating element.

Still further, each connection terminal holder may hold a plurality ofheating elements such that they are in face with the substrate holder,and the distances between the neighboring heating elements of theplurality of heating elements may be different from each other in part.

In this manner, it is possible to adjust distances, so that thedistances between the neighboring heating elements among the pluralityof heating elements supported by the connection terminal holders may beset as wide in part, and be narrow in the other part.

Thus, as described above, it is possible to form a thin film having auniform thickness effectively by adjusting the gap between the heatingelement at any position among the plurality of heating elementssupported by the connection terminal holders, and the connectionterminal holder, or by adjusting the distance between the neighboringheating elements among the plurality of heating elements supported bythe connection terminal holders, in addition to arranging the connectionterminals appropriately at desirable positions, in accordance with thearea of substrate to be processed and the process conditions.

In particular, in the case where a plurality of connection terminalholders are disposed to form a film on a large-area substrate, by makingthe gap between the heating element and the connection terminal holderat the boundary position of the neighboring connection terminal holderswhich are opposed to each other across a boundary between theneighboring connection terminal holders and the gap between the heatingelement and the connection terminal holder which are arranged at thepositions corresponding to the outer peripheral portion of thelarge-area substrate different from the gap between the heating elementand the connection terminal holder which are arranged at the otherpositions, it is possible to make the film thickness uniform effectivelyeven though the plurality of connection terminal holders are arranged.

In this connection, in the above-described heating element CVD system inaccordance with the present invention, each connection terminal holdermay hold a plurality of heating elements such that they are in face withthe substrate holder, and the gap between at least one or more heatingelement of the plurality of heating elements and the connection terminalholder may be different from the gap between the other heating elementand the connection terminal holder, and the distances between theneighboring heating elements of the plurality of heating elements may bedifferent from each other in part. In this manner, it is possible toform a film having a uniform thickness effectively over a large area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptional view showing an example of cross-sectionalconstitution of connection region between a heating element and aconnection terminal of a heating element CVD system in one preferredembodiment of the present invention;

FIG. 2 is a conceptional view showing a cross-sectional constitution ofmain portion of a connection region between a heating element and aconnection terminal of a heating element CVD system in another preferredembodiment of the present invention;

FIG. 3 is a conceptional view showing a cross-sectional constitution ofa connection region of a heating element connected to a connectionterminal in a heating element CVD system in a preferred embodiment ofthe present invention;

FIG. 4 is a conceptional view showing a cross-sectional constitution ofa connection region of a heating element connected to a connectionterminal in a heating element CVD system in another preferred embodimentof the present invention;

FIG. 5 is a conceptional view showing a cross-sectional constitution ofa connection region of a heating element connected to a connectionterminal in a heating element CVD system in still another preferredembodiment of with the present invention;

FIG. 6 is a conceptional view showing a cross-sectional constitution ofthe connection region of a heating element connected to a connectionterminal in a preferred embodiment of a heating element CVD system inaccordance with the present invention in which one connection terminalholder is disposed in a processing container;

FIG. 7 is a conceptional view showing a cross-sectional constitution ofthe connection region of a heating element connected to a connectionterminal in a preferred embodiment of a heating element CVD system inaccordance with the present invention in which two connection terminalholders are disposed in a processing container;

FIG. 8 is a detailed conceptional view of a connection terminal part Ain FIG. 7;

FIG. 9(a) is a schematic view of a connection terminal holder whenviewed from the surface to which a heating element is attached;

FIG. 9(b) is a schematic plane view of a connection terminal holder asto the case when a plurality of connection terminals are disposed toform a film on a large-area substrate;

FIG. 10 is a conceptional view showing a constitution of a heatingelement of a conventional heating element CVD system; and

FIG. 11 is a conceptional view showing a constitution of a part of aheating element of another constitution of a heating element of aconventional heating element CVD system.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will hereinafter bedescribed on the basis of the accompanying drawings.

FIG. 1 and FIG. 2 show a cross-sectional structure of a connection partbetween a heating element and a power supply mechanism in a preferredembodiment of a heating element CVD system in accordance with thepresent invention.

The structures of a processing container 1, a substrate holder 4, and anevacuation system 11 in a heating element CVD system in accordance withthe present invention are the same as those of a conventional heatingelement CVD system shown in FIG. 10, and hence are omitted in thedrawings. Further, like reference numerals are attached to memberssimilar to the members shown in FIG. 10.

In the embodiments shown in FIG. 1 and FIG. 2, a connection terminal310, which is the connection part between a heating element 3 and apower supply mechanism 30, is constituted as follows.

A connection terminal body 311 is held by a connection terminal holder 6having a first inside hollow portion 62 therein electrically insulatedby insulating bodies 317, 318.

The end part of a power supply line 32 from the power supply mechanism30 and the end part of the heating element 3 are connected to each othervia the connection terminal body 311. In the present embodiment, theyare connected to each other in the following manner. That is, the endpart of the power supply line 32 is connected to the connection terminalbody 311 by fixing the connection terminal body 311 to the connectionterminal holder 6 by means of a nut 313 with a washer 314 therebetween.And the end part of the heating element 3 is connected to the connectionterminal body 311 by pressing the end part of the heating element 3 ontothe connection terminal body 311 by means of a heating element pressingspring 315.

Further, a cap 312 is put on the connection terminal body 311 with aconnection terminal inside hollow portion 71 a existing between the cap312 and the connection terminal body 311 on the side where the end partof the heating element 3 is connected to the connection terminal body311 and without contacting the heating element 3. That is, the cap 312is put on the connection terminal body 311 with a gas passing hole 71 bas a gap between itself and the heating element 3.

In the embodiments shown in FIG. 1 and FIG. 2, the upper part of cap 312is fixed to the connection terminal body 311 with a C-ring 316interposed therebetween.

By turning the cap 312 by 180 degrees, a heating element pressing spring315 can be pressed or loosened. In this manner, pressing the end part ofthe heating element 3 onto the connection terminal body 311 by theheating element pressing spring 315, when the end part of the heatingelement 3 is connected to the connection terminal body 311, is adjusted,and loosening the heating element pressing spring 315, when the endportion of the heating element 3 is disconnected and dismounted from theconnection terminal body 311, is adjusted, and thus the heating element3 can be easily mounted onto or dismounted from the connection terminal310. FIG. 3, FIG. 4, and FIG. 5 show other embodiments in accordancewith the present invention. In these embodiments, only the connectionterminal 310 is different from the connection terminals 310 in theembodiments shown in FIG. 1 and FIG. 2, so that in FIG. 3, FIG. 4, andFIG. 5, only the connection terminal 310 is shown in an enlarged view.

The embodiments in FIG. 1 to FIG. 5 are common in that the connectionregion of the heating element 3 to the connection terminal body 311 isnot exposed to a space in the processing container 1. In the embodimentsshown in FIG. 3 to FIG. 5, however, a cylindrical body 320 is providedon the cap 312 at the side of the inner space of the processingcontainer 1, which is different from the connection terminal 310 in theembodiments shown in FIG. 1 and FIG. 2. In the embodiment shown in FIG.5, a cylindrical body 320 is provided on the cap 312 directed to theside of the inner space of the processing container 1, which is onlydifferent from the connection terminal 310 in the embodiments shown inFIG. 1 and FIG. 2. The embodiment shown in FIG. 4 is different in thatit does not have a structure in which a gas passing hole 71 b betweenthe heating element 3 and the cap 312 does not communicate with theinside of a connection terminal holder 6. The embodiment shown in FIG. 3is different in that the gas passing hole 71 b between the heatingelement 3 and the cap 312 does not communicate with the inside of theconnection terminal holder 6 and in that a gap (connection terminalinside hollow portion 71 a) is not provided between the cap 312 and theconnection terminal body 311.

In any one of the embodiments shown in FIG. 1 to FIG. 5, the connectionregion of the heating element 3 to the connection terminal body 311 isnot exposed to the space in the processing container 1. For this reason,it is possible to prevent a raw material gas such as a silane gas or thelike from contacting the connection region (a part of heating element 3where the temperature is slightly low) of the heating element 3connected to the connection terminal body 311, when the film is formed.

In the embodiments shown in FIG. 1, FIG. 2, and FIG. 5, gas can bepassed, by a gas flow passage 319, through the connection terminalinside hollow portion 71 a existing between the cap 312 and theconnection terminal body 311 and the first inside hollow portion 62 inthe connection terminal holder 6. Further, there is provided a gasintroduction system 61 for introducing gas into the first inside hollowportion 62 in the connection terminal holder 6.

In the embodiments shown in FIG. 1, FIG. 27 and FIG. 5, the gas passage319 is drawn at the side of a portion where the heating element 3 isconnected to the connection terminal body 311, but it is possible toface the gas passage 319 to the portion where the heating element 3 isjust connected to the connection terminal body 311.

The gas introduction system 61 is a gas introduction system forintroducing any one gas of hydrogen, argon, helium, neon, krypton,xenon, nitrogen, or ammonia, or a mixed gas containing two or more kindsof these gases. This gas supply system has the same constitution as theraw material gas introduction system 21 shown in FIG. 10.

In the embodiments shown in FIG. 1, FIG. 2, and FIG. 5, as describedabove, the gas (purge gas) introduced by the gas introduction system 61is introduced into the processing container 1 through the connectionterminal inside hollow portion 71 a and the gas passing hole 71 b.Accordingly, it is possible to further effectively prevent the rawmaterial gas such as a silane gas or the like from contacting theconnection region of the heating element 3 (the part of the heatingelement 3 where the temperature is slightly low) connected to theconnection terminal body 311, when the film is formed. Further, in theseembodiments, it is possible to prevent the cleaning gas from contactingthe connection region of the heating element 3 (the part of the heatingelement 3 where the temperature is slightly low) connected to theconnection terminal body 311, when the deposited film is removed (acleaning operation is performed).

In this connection, while only one heating element 3 is shown in theembodiment shown in FIG. 1, the number of the heating elements isarbitrarily selected and, needless to say, the connection terminalholder 6 is provided with the connection terminals 310 of the numbercorresponding to the number of the heating elements 3.

Further, in FIG. 1, the raw material gas supply system 21, described inthe conventional heating element CVD system shown in FIG. 10, isconnected to the raw material gas supply unit 22 having blowing-outopenings 211 for supplying the raw material gas into the processingcontainer 1, and the raw material gas supply unit 22 is disposed suchthat it surrounds the heating element 3.

In this connection, in the case where a plurality of heating elements 3are used, the raw material gas supply unit 22 may be arranged such thatit surrounds all the heating elements 3, but in order to form a uniformfilm, it is desirable to arrange the raw material gas supply units 22 sothat the raw material gas supply units 22 surround each heating element3.

The embodiment shown in FIG. 2 is different from the embodiment shown inFIG. 1 in that the connection terminal holder 6 has the second insidehollow portion 23. A gas supply system 21 is connected to the secondinside hollow portion 23. And the second inside hollow portion 23 has aplurality of blowing-out openings 212 made in the surface on the side inface with the substrate holder 4. The second inside hollow portion 23communicates with the space in the processing container 1 only throughthe gas blowing-out openings 212. That is, as shown in FIG. 2, the firstinside hollow portion 62 is separated from the second inside hollowportion 23.

The other parts in the embodiment shown in FIG. 2 are the same as thosein the embodiment shown in FIG. 1, so the same reference numerals areattached to the members similar to the members shown in FIG. 1 and FIG.10.

While only one heating element 3 is shown in the embodiment shown inFIG. 2, the number of the heating elements 3 is arbitrarily selectedand, needless to say, the connection terminal holder 6 is provided withthe connection terminals 310 of the number corresponding to the numberof the heating elements 3.

In the embodiment shown in FIG. 2, the raw material gas is supplied intothe processing container 1 through the blowing-out openings 212 from thesecond inside hollow portion 23. Therefore, even if a substrate to beprocessed has a large area, by enlarging the connection terminal holder6 and increasing the number of the heating elements 3, the raw materialgas can be supplied to the whole surface of the large-area substrate,whereby a uniform film can be formed. That is, this embodiment caneasily be applied to a substrate having a large area.

When a silicon film is formed by the conventional heating element CVDsystem shown in FIG. 10, a silane gas and a hydrogen gas are introducedinto the processing container 1 from the respective raw material gassupply systems 21 (only one system is shown in FIG. 10) via the gassupply unit 2.

In contrast to this, in the present invention, preferably, therespective gases can be introduced into the processing container 1 asfollows. That is, in the case of the embodiment shown in FIG. 1, onlythe silane gas can be introduced into the processing container 1 fromthe raw material gas supply system 21 through the blowing-out openings211 via the raw material gas supply unit 22. The hydrogen gas can beintroduced into the processing container 1, as shown by an arrow 72,from the gas supply system 61 through the first inside hollow portion 62of the connection terminal holder 6, the gas flow passage 319, theconnection terminal inside hollow portion 71 a, and the gas passing hole71 b. In the case of the embodiment shown in FIG. 2, the silane gas canbe introduced into the processing container 1 through the blowing-outopenings 212 from the second inside hollow portion 23 of the connectionterminal holder 6, and the hydrogen gas can be introduced into theprocessing container 1, as shown by an arrow 72, from the gas supplysystem 61 through the first inside hollow portion 62 of the connectionterminal holder 6, the gas flow passage 319, the connection terminalinside hollow portion 71 a, and the gas passing hole 71 b.

This flow of the hydrogen gas can prevent the silane gas, introducedinto the processing container 1 from the raw material gas supply unit22, and/or the activated species originated from the silane gas, whichare decomposed and/or activated on the surface of the heating element 3,from entering into the connection terminal inside hollow portion 71 abetween the cap 312 and the connection terminal body 311. This canprevent the silane gas and/or activated species originated from thesilane gas from contacting the connection terminal body 311 of theheating element 3, whereby the portion, where its temperature isslightly low, can be prevented from being changed to a silicide anddegraded. In this respect, the embodiment shown in FIG. 5, in which thecylindrical body 320 is provided on the cap 312 directed to the side ofthe inner space of the processing container 1, can further effectivelyenhance such effect.

Here, the gas, which is introduced into the connection terminal insidehollow portion 71 a between the cap 312 and the connection terminal body311 from the gas supply system 61 through the first inside hollowportion 62 of the connection terminal holder 6 and the gas flow passage319, is not limited to the hydrogen gas, but may be any one gas ofargon, helium, neon, krypton, or xenon, or a mixed gas of two or morekinds of these gases. The use of any gas or mixed gas of this kinds canprevent the deterioration of the heating element 3 in the same way.

However, even in this case, because the introduction of the hydrogen gasis necessary to polycrystallize the silicon film and to improve theefficiency of the polycrystallization of the silicon film. Therefore,the hydrogen gas may be mixed with any one of the above-mentioned gasother than the hydrogen gas and be introduced into the processingcontainer 1 through the first inside hollow portion 62 of the connectionterminal holder 6, the gas flow passage 319, the connection terminalinside hollow portion 71 a, and the gas passing hole 71 b, as shown byan arrow 72, or from the raw material gas supply unit 22 through theblowing-off openings 211 (in the case of the embodiment shown in FIG.1), or from the second inside hollow portion 23 of the connectionterminal holder 6 through the blowing-off openings 212 (in the case ofthe embodiment shown in FIG. 2). However, preferably, it is recommendedthat the hydrogen gas is introduced in the mixed state through theconnection terminal 310 because this is more effective.

Further, in the formation of a silicon nitride film, it is absolutelynecessary to introduce a silane gas and an ammonia gas for effectivelyforming a silicon nitride film. Hence, in the formation of the siliconnitride film by means of the conventional heating element CVD systemshown in FIG. 10, the silane gas and the ammonia gas are introduced intothe processing container 1 from the respective raw material gas supplysystems 21 (only one system is shown in FIG. 10) via the gas supply unit2.

In contrast to this, in the present invention, preferably, only thesilane gas is introduced into the processing container 1 from the rawmaterial gas supply system 21, in the case of the embodiment shown inFIG. 1, through the blowing-out openings 211 from the raw material gassupply unit 22. The ammonia gas can be introduced into the processingcontainer 1 from the gas supply system 61 via the first inside hollowportion 62 of the connection terminal holder 6, the gas flow passage319, the connection terminal inside hollow portion 71 a, and the gaspassing hole 71 b, as shown by an arrow 72. In the case of theembodiment shown in FIG. 2, the silane gas is introduced into theprocessing container 1 through the blowing-out openings 212 from thesecond inside hollow portion 23 of the connection terminal holder 6. Theammonia gas can be introduced into the processing container 1 from thegas supply system 61 via the first inside hollow portion 62 of theconnection terminal holder 6, the gas flow passage 319, the connectionterminal inside hollow portion 71 a, and the gas passing hole 71 b, asshown by an arrow 72.

As is the above-mentioned case of the formation of the silicon film,this can prevent the silane gas, introduced into the processingcontainer 1 from the raw material gas supply unit 22, and/or theactivated species originated from the silane gas, which are decomposedand/or activated on the surface of the heating element 3, from enteringinto the connection terminal inside hollow portion 71 a between the cap312 and the connection terminal body 311. This can prevent the silanegas and/or activated species originated from the silane gas fromcontacting the connection terminal body 311 of heating element 3,whereby a portion, where its temperature becomes slightly slow, can beprevented from being changed to silicide and degraded. The embodimentshown in FIG. 5, in which the cylindrical body 320 is provided on thecap 312 directed to the side of the inner space of the processingcontainer 1 can further effectively produce such effect.

Here, in place of the ammonia gas, the mixed gas of ammonia gas and anyone gas of hydrogen, argon, helium, neon, krypton, or xenon, or a mixedgas of two or more kinds of these gases may be used. If these gases areused, they can prevent the deterioration of the heating element 3 in thesame way.

However, even in this case, the introduction of the ammonia gas isnecessary because of the reason described above. Thus, the ammonia gasmay be mixed with any one of the above-mentioned gases other than theammonia gas and be introduced into the processing container 1 throughthe first inside hollow portion 62 of the connection terminal holder 6,the gas flow passage 319, the connection terminal inside hollow portion71 a, and the gas passing hole 71 b, as shown by an arrow 72, or fromthe raw material gas supply unit 22 through the blowing-off openings 211(in the case of the embodiment shown in FIG. 1), or from the secondinside hollow portion 23 of the connection terminal holder 6 through theblowing-off openings 212 (in the case of the embodiment shown in FIG.2). However, preferably, it is recommended that the ammonia gas isintroduced in the mixed state through the connection terminal 310because this is more effective.

In the embodiment in accordance with the present invention, when a filmdeposited on the inside of the processing container 1 is removed(cleaned), each cleaning gas is introduced as follows.

In the case of the embodiment shown in FIG. 1, the cleaning gas isintroduced into the processing container 1 from a cleaning gas supplysystem (not shown), the construction of it is similar to the rawmaterial gas supply system 21, through the blowing-out openings 211 fromthe raw material gas supply unit 22, and any one gas of hydrogen, argon,helium, neon, krypton, xenon, nitrogen, or ammonia, or a mixed gas oftwo or more kinds of these gases is introduced into the processingcontainer 1 from the gas supply system 61 through the first insidehollow portion 62 of the connection terminal holder 6, the gas flowpassage 319, the connection terminal inside hollow portion 71 a, and thegas passing hole 71 b, as shown by an arrow 72. In the case of theembodiment shown in FIG. 2, the cleaning gas is introduced into theprocessing container 1 through the blowing-out openings 212 from thesecond inside hollow portion 23 of the connection terminal holder 6, andany one gas of hydrogen, argon, helium, neon, krypton, xenon, nitrogen,or ammonia, or a mixed gas of two or more kinds of these gases isintroduced into the processing container 1 from the gas supply system 61via the first inside hollow portion 62 of the connection terminal holder6, the gas flow passage 319, the connection terminal inside hollowportion 71 a, and the gas passing hole 71 b, as shown by an arrow 72.

This can prevent the cleaning gas itself and/or the activated speciesoriginated from the cleaning gas, which are decomposed and/or activatedon the surface of the heating element 3, from entering into theconnection terminal inside hollow portion 71 a between the cap 312 andthe connection terminal body 311. This can prevent the portion of theheating element 3 (connection region connected to the connectionterminal body 311) where its temperature is slightly slow from beingetched and degraded. Here, the embodiment shown in FIG. 5, in which thecylindrical body 320 is provided on the cap 312 directed to the side ofthe inner space of the processing container 1 can further effectivelyproduce such effect.

In the cases of the embodiments shown in FIG. 3, FIG. 4, and FIG. 5, thecylindrical body 320 provided on the cap 312 directed to the side of theinner space of the processing container 1 is formed of, for example,alumina and, for example, in an inside diameter φ of 3 mm and a length Lof 20 mm.

In the embodiment shown in FIG. 6, when a silicon film was formed withthe temperature of the heating element 3 at 1800° C. in the state wherethe introducing operation of the hydrogen gas or the like into theprocessing container 1 from the inside of the connection terminal holder6 though the connection terminal inside hollow portion 71 a, the gaspassing hole 71 b, and the hollow portion of the cylindrical body 320,as shown by the arrow 72, was stopped, the connection region of theheating element 3 to the connection terminal body 311 was not changed tosilicide. Further, in the embodiments shown in FIG. 3 and FIG. 4, when asilicon film was formed with the temperature of the heating element 3at. 1800° C. in the state where the introducing operation of thehydrogen gas or the like into the processing container 1 from the insideof the connection terminal holder 6 though the gas passing hole 71 b andthe hollow portion of the cylindrical body 320, as shown by the arrow72, was stopped, the connection region of the heating element 3 to theconnection terminal body 311 was not changed to silicide.

In the embodiment shown in FIG. 5, as described in the embodiments shownin FIG. 1 and FIG. 2, the hydrogen gas or the like can be introducedinto the processing container 1, as shown by the arrow 72, from theinside of the connection terminal holder 6 through the gas passing hole71 b and the hollow portion of the cylindrical body 320. Hence, theintroduction of this purge gas can further effectively prevent theconnection region of the heating element 3 to the connection terminalbody 311 from being changed to silicide when the film is formed and frombeing etched by the reaction with the cleaning gas when the depositedfilm is removed (cleaned).

In the embodiments shown in FIG. 4 and FIG. 5, a structure has beenshown in which the cylindrical body 320 is mounted on the cap 312directed to the side of the inner space of the processing container 1but, needless to say, even a structure in which the cylindrical body 320is mounted toward the inside of the cap 312 (on the side opposite to thesubstrate holder) can produce the same working and effect.

Further, in the above-described embodiments in accordance with thepresent invention, a structure has been shown in which the cap 312 ismounted on the connection terminal body 311 singly or in the state wherethe cylindrical body 320 is mounted on the cap 312, but a structure inwhich the cap 312 is mounted on the connection terminal holder 6 may beused and can produce the same working and effect. However, suchstructure has the possibility that if the cap and the cylindrical bodyare made of a metallic material, the heating element 3 is put intocontact with the cap and the cylindrical body by thermal strain or thelike to develop an electric short circuit. Therefore, it is preferablethat the cap and the cylindrical body are formed of an insulatingmaterial such as alumina or the like or a composite material made of ametallic material covered with the insulating material such as aluminaor the like.

FIG. 6 shows a cross-sectional structure in which one connectionterminal holder 6 described above is disposed in the processingcontainer 1. As shown in FIG. 6, the connection terminal holder 6 holdsthe connection terminal 310 for electrically connecting the power supplymechanism 30 to the heating element 3 while electrically insulating itby means of insulating members 317, 318. The connection terminal holder6 holds the heating element 3 in face with the substrate holder 4 and isa structure independent of the processing container 1. The connectionterminal holder 6 is connected to the power supply mechanism 30, the rawmaterial gas supply system 21, and the gas introduction system 61.

The structure shown in FIG. 6 is different from those in the embodimentsshown in FIG. 1 to FIG. 5 in that a power supply plate 53 connected tothe power supply line 32 is sandwiched between a nut 313 and theconnection terminal body 311, but the basic structure of the otherportion is the same as those of the embodiments shown in FIG. 1 to FIG.5. Thus, the same reference characters are attached to the memberssimilar to the members described in the embodiments in FIG. 1 to FIG. 5and their description will be omitted.

The heating element CVD system in accordance with the present inventionmay be constituted in a structure in which a plurality of connectionholders 6 described in FIG. 1 to FIG. 6 are disposed in the processingcontainer 1. FIG. 7 and FIG. 8 show a cross-sectional structure of theconnection part of a heating element and a power supply mechanism in thecase that a plurality of connection holders 6 are used. The part shownin FIG. 7 and FIG. 8 corresponds to the part shown in FIG. 6. FIG. 8shows the part A in FIG. 7 in detail. As is the case of FIG. 1 to FIG.6, the structures of the processing container 1, the substrate holder 4and the exhaust system, etc. are the same as in the conventional heatingelement CVD system shown in FIG. 10, and FIG. 11 described above, so theillustration and description will be omitted.

Further, the embodiment shown in FIG. 7 and FIG. 8 is different from theembodiment shown in FIG. 6 in that the nut 313 has an object of fixingthe connection terminal body 311 to the connection terminal holder 8and, at the same time, of connecting the power supply plates 53, 54 tothe connection terminal body 311. However, the other basic structure andconfiguration are the same as in the embodiments shown in FIG. 1 to FIG.6. Therefore, the same reference characters are attached to the memberssimilar to members shown in FIG. 1 to FIG. 6 and the description will beomitted.

In the embodiments shown in FIG. 6 to FIG. 8, the heating element 3 isconnected to and held by the connection terminal body 311 by a coilspring 330 which is different from the heating element pressing spring315 in the embodiments shown in FIG. 1 to FIG. 5. This can mount ordismount the heating element 3 on or from the connection terminal body311 with a single motion without the turning operation of the cap 312 inthe embodiments shown in FIG. 1 to FIG. 5.

The embodiment shown in FIG. 7 is different from the embodiment shown inFIG. 6 in that two connection terminal holders 8 are disposed in theprocessing container 1 and that the connection part of the connectionterminal and the power supply mechanism and the wiring part forelectrically connecting the connection terminals are built in theconnection terminal holder 8. Then, the difference in a structurebetween the embodiment shown in FIG. 7 and the embodiment shown in FIG.6 will be described specifically in the following.

In the embodiment shown in FIG. 7 and FIG. 8, the connection part of theconnection terminal 310 and the power supply mechanism 30 is coveredwith the first inside hollow portion 62. This can prevent the connectionpart of the connection terminal 310 and the power supply mechanism 30from being exposed to the space in the processing container 1. Further,also the power supply plate 54 (between the connection terminals) thatis the wiring part for electrically connecting the connection terminalsis covered with the first inside hollow portion 62, thereby is preventedfrom being exposed to the space in the processing container 1.

In this connection, in the embodiments shown in FIG. 7 and FIG. 8, theconnection terminal body 311 is provided with a gas flow passage 319 forconnecting the inside hollow portion 47 in the connection terminalholder 8 to the connection terminal inside hollow portion 71 a. Thus,the gas introduced from the gas introduction system 61 fills the firstinside hollow portion 62 and is introduced into the next inside hollowportion 47 through an inside space through hole 46. The gas is furtherflowed into the connection terminal inside hollow portion 71 a in theconnection terminal body 311 through the gas flow passage 319. Then, thegas passes near the heating element 3 and the coil spring 330 to thenon-contact part between the heating element 3 connected to theconnection terminal 310 and the connection terminal holder 8 That is,the gas flows to the space in the processing container 1 through the gaspassing hole 71 b, as shown by the arrow 72.

In the heating element CVD system shown in FIG. 7 and FIG. 8, in theconnection terminal holder 8, the second inside hollow portion 23 intowhich the raw material gas or the cleaning gas is introduced isseparated from the first inside hollow portion 62. The connectionterminal 310 and the power supply plates 53, 54 are disposed in thefirst inside hollow portion 62 that is separated from the second insidehollow portion. Further, as described above, the gas introduced from thegas introduction system 61 flows from the first inside hollow portion 62to the gas passing hole 71 b. So that, the connection terminal 310 andthe power supply plates 53, 54 are not affected by the raw material gasand the cleaning gas. As described above, the connection terminal 310and the power supply plates 53, 54 are not exposed to the space in theprocessing container 1. Therefore, these members are not degraded byactivated species originated from the raw material gas (silane gas) bybeing decomposed and/or activated on the surface of the heating element3.

Further, in the heating element CVD system shown in FIG. 7 and FIG. 8,there are provided a plurality of connection terminal holders 8 that areindependent in a structure of each other. For this reason, even if afilm is formed on a large-area substrate of a size of over 1 m, it isnot necessary to manufacture one large connection terminal holder havingan area equal to or larger than the area of the substrate. That is, itis recommended that a plurality of connection terminal holders 8 whichare similar to each other but independent of each other may bemanufactured and disposed according to the area of a substrate to beprocessed. Therefore, it is possible to provide a heating element CVDsystem for forming a film on a large-area substrate at low cost andeasily.

This will be described with reference to FIG. 9(a), (b).

FIG. 9(a) is a schematic view of the connection terminal holder 8 whenviewed from the side to which the heating element 3 is mounted. Theconnection regions of the heating elements 3 connected to the connectionterminals 310 are covered with the cylindrical bodies 320. In theexample of FIG. 9(a), the connection terminal holder 8 has a size of 275mm in length×640 mm in width. A single heating element 3 is 170 mm inlength. Five heating elements 3 are arranged in parallel in thelongitudinal direction and three groups of five heating elements 3 arearranged in the lateral direction, so fifteen heating elements 3 aresupported by the connection terminal holder 8

FIG. 9(b) is a schematic plane view of the connection terminal holders 8and showing the embodiment where a plurality of connection terminalholders 8 are arranged in order to be applied to form a large-areasubstrate. The size of the substrate is 400 mm in length and 960 mm inwidth (shown with a dotted line denoted by a reference number 81). Inthis case, four connection terminal holders 8 shown in FIG. 9(a) arearranged in parallel. This corresponds, as a whole, to one connectionterminal holder of a size of 640 mm in length and 1100 mm in width.

According to the heating element CVD system of the present invention, asshown in FIG. 9(b), by arranging the plurality of connection terminalholders 8, even when a film is to be formed on a large-area substrate ofa size of over 1 m, it is not necessary to manufacture a largeconnection terminal holder having a large area equal to or larger thanthe area of the substrate.

The embodiment shown in FIG. 7 shows a cross-sectional view of theheating element CVD system provided with two connection terminal holders8. According to the heating element CVD system of the present invention,it is recommended that a plurality of connection terminal holders 8 maybe arranged in accordance with the size of a substrate on which a filmis to be formed. For this reason, the connection terminal holder 8,which is one independent structure, can be formed in a size easilyprocessed and thus can be manufactured at low cost and easily. Further,the weight of one connection terminal holder 8 is also reduced.Therefore, the connection terminal holder 8 can be easily mounted on theprocessing container (vacuum container) 1 when it is manufactured andmaintained. Still further, an opening for putting the connectionterminal holder 8 into the processing container 1 can be reduced insize, whereby the manufacturing cost of the processing container 1 canbe reduced.

In the heating element CVD system in accordance with the presentinvention, the distance between the heating elements 3 mounted on theconnection terminal holder 6 or 8 and/or the gap between the connectionterminal holder 6 or 8 and the heating element 3 (30 mm in the exampleshown in FIG. 9(a)) can be changed. The distance can be changed bychanging the position where the connection terminal 310 is mounted onthe connection terminal holder 6 or 8. Further, as shown in FIG. 7, thegap can be changed by changing the shape or configuration of the heatingelement 3 or 3 a mounted on the connection terminal 310. In this manner,according to the area of the substrate and the process conditions, byadjusting the gap between the connection terminal holder and the heatingelement, that is, eventually, by adjusting the gap between the substrateand the heating element 3 and/or the distance between the heatingelements mounted on the connection terminal holder, it is possible toeffectively form a film of a uniform thickness in case of arranging theplurality of connection terminal holders 8.

For example, in the embodiment shown in FIG. 7, the gaps between theheating elements 3 a, 3 b, and the connection terminal holders 8 at theboundary position of the neighboring connection terminal holders are setto be smaller than the gap between the heating element 3 and theconnection terminal holder 8 at a position away from the boundaryposition of the connection terminal holders. In this manner, by settingthe gap between at lest one or more heating element 3 of the pluralityof heating elements supported by the connection terminal holder 8 andthe connection terminal holder 8 different from the gap between theother heating elements 3 and the connection terminal holder 8, thethickness of the film can be made uniform. That is, by adjusting the gapbetween the substrate and the heating elements 3, the thickness of thefilm can be made uniform, for example, in case of arranging theplurality of connection terminal holders 8 or at the outer peripheralportion of the large-area substrate. In particular, by making the gapbetween the heating elements 3 a, 3 b and the connection terminalholders at the boundary position of the neighboring connection terminalholders different from the gap between the heating element and theconnection terminal holder at the other position, the thickness of thefilm can be made uniform even if the plurality of connection terminalholders 8 are arranged.

(Example of Test of Film Thickness Distribution)

As shown in FIG. 9(b), a film was formed on a large-area substrate bythe use of the heating element CVD system in accordance with the presentinvention in which four connection terminal holders 8 shown in FIG. 9(a)were arranged with no gap between them and the uniformity of the filmthickness was studied.

As shown in FIG. 9(b), the gap between the heating elements 3 was notvaried even at the connection portion of the neighboring connectionterminal holders 8, whereby the four connecting terminal holders 8 whichwere arranged adjacently to each other were made to correspond to oneconnection terminal holder.

A glass substrate 81 of a size of 960 mm×400 mm was arranged on thesubstrate holder 4 and then a film was formed under the followingconditions:

Pressure in processing container 1 2 Pa Flow rate of SiH₄ 100 ml/min innormal state Flow rate of H₂  55 ml/min in normal state Temperature ofheating element 3 1750° C. Distance between heating element 45 mm andsubstrate

The average film forming speed at 11 points, shown by a mark ▪, on theglass substrate 81 was 5.3 angstrom/sec (0.53 nm/sec) and itsdistribution was as comparatively good as ±7.5%

As a result, it was found that even in the case when a film was formedon a large-area substrate of 1 m in length, a uniform film thicknessdistribution of ±10 or less could be ensured by the use of the heatingelement CVD system of the embodiment shown in FIG. 7 and FIG. 8 in whicha plurality of independent connection terminal holders 8 are arranged inparallel, thereby being made to correspond to one connection terminalholder so as to be applied to the formation of the film on thelarge-area substrate. Further, in this case, it is possible to preventthe film thickness distribution from being made nonuniform formconnection terminal holder to connection terminal holder in case of useof plural connection terminal holders or at the outer peripheral portionof the large-area substrate by adjusting the distance between theheating elements 3 mounted on the connection terminal holders 8 and/orby adjusting the gap between the substrate and the heating element 3 byadjusting the gap between the connection terminal holder 8 and theheating elements 3 according to the area of the substrate and theprocess conditions.

In the heating element CVD system in accordance with the presentinvention described above, the heating element 3 is connected to theconnection terminal body 311 by the heating element pressing spring 315or by the coil spring 330, as the material of the heating elementpressing spring 315 or the coil spring 330, metal such as berylliumcopper, stainless steel, or Inconel, or ceramics can be used. Further,the heating element CVD system in accordance with the present inventioncan be applied even to the cases when any halogen-based cleaning gassuch as fluorine (F₂), chlorine (Cl₂), nitrogen trifluoride (NF₃),methane tetrafluoride (CF₄), ethane hexafluoride (C₂F₆), propaneoctafluoride (C₃F₈), carbon tetrachloride (CCl₄), methane chloridetrifluoride (CClF₃), ethane chloride pentafluoride (C₂ClF₅), chlorinetrifluoride (ClF₃), sulfur hexafluoride (SF₆) is used as the cleaninggas when the cleaning process is performed

While preferred embodiments in accordance with the present inventionhave been described with reference to the accompanying drawings up tothis point, it will be understood that the present invention is notlimited to these embodiments. On the contrary, the present invention maybe modified further variously within the spirit and scope of theinvention as defined by the appended claims.

For example, the formation of the silicon film and the silicon nitridefilm in the above-described embodiments in accordance with the presentinvention is the application of the heating element CVD system of thepresent invention to the formation of the films, and the heating elementCVD system of the present invention can be applied also to the formationof the other films. Further, while the silane gas is used in theformation of the film in the above-mentioned embodiments of the presentinvention, disilane (Si₂H₅), trisilane (Si₃H₈), and tetraethoxysilane(TEOS) other than the silane gas can be used also in the application ofthe present invention.

Further, a method of connecting the heating element 3 to the connectionterminal body 311 is not limited to a method in which the heatingelement pressing spring 315 or the coil spring 330 is used, but a methodin which a screw is used may be adopted.

Still further, while a wire-shaped heating element 3 is used in theheating element CVD system in accordance with the present invention, theheating element may be shaped in a foil, and the wire-shaped heatingelement may be disposed in the shape of a coil or the like. However, inthe case when a coil-shaped heating element is used, it is desirable touse a heating element which is shaped in a wire at least at the gap inthe connection terminal. This is because it is important to set the gaspassing hole 71 b between the cap 312 and the heating element 3 narrowso that the gas passing hole 71 b can effectively prevent the rawmaterial gas and the activated species thereof or the cleaning gas andthe activated species thereof from entering into the connection terminalinside hollow portion 71 a in the cap 312, so it is desirable to reducethe area of the gap.

In the embodiment shown in FIG. 6, only the example in which one heatingelement 3 is mounted on one connection terminal holder 6 is shown.Further, in the embodiment shown in FIG. 7, only the example in whichtwo heating elements 3, 3 a or 3, 3 b are mounted on one connectionterminal holder 8, respectively, is shown. However, the number ofheating elements 3 mounted on one connection terminal holder 6 or 8 maybe selected arbitrarily. Further, needless to say, connection terminals310 of the number corresponding to the number of heating elements 3 areheld by the connection terminal holder 8.

Further, in the embodiment shown in FIG. 7, the example in which twoconnection terminal holders 8 are used is shown, but it is natural thatthe number of connection terminal holders 8 may be increased arbitrarilyin accordance with the area of the substrate on which the film isformed.

Further, in the embodiment shown in FIG. 7 and FIG. 8, the gas such ashydrogen introduced into the first inside hollow portion 62 from the gasintroduction system 61 is flowed from the first inside hollow portion 62into the connection terminal inside hollow portion 71 a of theconnection terminal body 311 through the inside space through hole 46,the inside space 47, the gas flow passage 319 and is introduced into thespace in the processing container 1 through the non-contact portionbetween the heating element 3 connected to the connection terminal 310and the connection terminal holder 8, that is, the gas passing hole 71b. However, the first inside hollow portion 62 communicating with a paththrough which the gas such as hydrogen introduced into the connectionterminal holder 8 is introduced into the space of the processingcontainer 1 through the gas passing hole 71 b may not be constituted, inparticular, in a structure in which it separated from the inside space47 and communicates with the inside space 47 through the inside spacethrough hole 46, but may be constituted in a structure in which itcommunicates directly with the connection terminal inside hollow space71 a of the connection terminal body 311 through the gas flow passage319 from the first inside hollow portion 62.

According to the heating element CVD system in accordance with thepresent invention, the connection region of the heating elementconnected to the connection terminal is not exposed to the space in theprocessing container, so that it is possible to prevent the raw materialgas such as silane gas or the like from contacting a portion of theheating element where temperature is slightly low (connection region ofthe heating element) and degrading the said portion (changing the saidportion into suicide).

Further, if a configuration is adopted in which the connection region ofthe heating element connected to the connection terminal is covered witha member in the form in which the said member does not contact theconnection region, that is, in such a way that there is a gap betweenthe said member and the connection terminal and that there is a gapbetween the said member and the heating element, thereby the saidconnection region of the heating element is prevented from being exposedto the space in the processing container, and a purge gas is flowedthrough the said gap from the side of connection portion to theprocessing container, it is possible to prevent the connection region ofthe heating element where temperature is slightly lower than apredetermined high temperature (that is, the connection region of theheating element where the temperature is lower than about 1600° C. whenthe film is formed and lower than about 2000° C. when the cleaningprocess is performed) from being degraded (being changed into silicide)by the raw material gas when the film is formed and, further, from beingetched by the reaction with the cleaning gas when the cleaning processis performed.

As a result, it is possible to prevent the heating element from beingdegraded by the raw material gas when the film is formed and thus tostabilize a film forming environment and further to prevent the heatingelement from reacting with the cleaning gas when the deposited film isremoved. Further, it is possible to reduce the frequency of replacementof the heating element that accompanies the breaking of the vacuum tothe atmosphere. These effects can improve productivity.

In this manner, it is possible to provide a heating element CVD systemthat can elongate the life of the heating element, stabilize the filmforming environment, and improve productivity.

Further, it is possible to prevent the connection terminal that is theconnection part between the heating element and the power supplymechanism and the connection wiring between the connection terminalsfrom being exposed to the space in the processing container (vacuumchamber) and thus it is possible to select a material suitable for theconnection terminal and the connection wiring without worrying that theyare being degraded by the activated gas.

Still further, according to the present invention, it is possible tomeet with forming of film on a large-area substrate of a size of over 1m and to provide a heating element CVD system capable of ensuring auniform film thickness.

According to the present invention, it is possible to provide a heatingelement CVD system that can elongate the life of a heating element andstabilize a film forming environment and has a high productivity andrealize a uniform film thickness even when a film is formed on alarge-area substrate.

What is claimed is:
 1. A heating element CVD system comprising: a processing container in which a predetermined processing is performed to a substrate held by a substrate holder disposed therein; an evacuation system which is connected to the processing container and evacuates it to a vacuum; a raw material gas supply system for supplying a predetermined raw material gas into the processing container; and a heating element which is disposed in the processing container and is supplied with electric power from a power supply mechanism, thereby being heated to high temperatures, wherein the raw material gas introduced into the processing container from the raw material gas supply system is decomposed and/or activated by the heating element kept at high temperatures to form a thin film on the substrate held by the substrate holder, wherein one or a plurality of connection terminal holders is placed in the processing chamber; each of the said connection terminal holders holds a plurality of connection terminals at a predetermined position with electrically insulating therebetween; each of the said connection terminals connects the heating elements to the power supply mechanism electrically; the said heating elements connected to the connection terminals are supported in face with the substrate holder; and a connection region of the heating element connected to the connection terminal is not exposed to a space in the processing container.
 2. A heating element CVD system according to claim 1, wherein the connection region of the heating element connected to the connection terminal is covered with a cylindrical body or a plate that is made of an insulating substance, a metal, or a composite of these materials and covers the connection region with a gap between the cylindrical body or the plate and the heating element.
 3. A heating element CVD system according to claim 1, wherein the connection region of the heating element connected to the connection terminal is covered with a cylindrical body or a plate that is made of an insulating substance, a metal, or a composite of these materials and covers the connection region with a connection terminal inside hollow portion between the cylindrical body or the plate and the connection terminal and with a gap between the cylindrical body or the plate and the heating element.
 4. A heating element CVD system according to claim 1, wherein the each of connection terminal is constituted by a connection terminal body and a cap put on the connection terminal body with a gap between itself and the heating element, and wherein a connection terminal inside hollow portion is formed between the cap and the connection terminal body.
 5. A heating element CVD system according to claim 1, wherein each connection terminal holder has a first inside hollow portion, and wherein the connection region of the heating element connected to each of a plurality of connection terminals held at the predetermined position of the connection terminal holder in the electrically insulated state is covered with a cylindrical body or a plate made of an insulating material or a metal or a composite material of these materials, which covers the connection region with the connection terminal inside hollow portion between the cylindrical body or the plate and the connection terminal and with a gas passing hole between the cylindrical body or the plate and the heating element, and wherein the connection terminal inside hollow portion communicates with the first inside hollow portion to which a gas introduction system for introducing gas is connected.
 6. A heating element CVD system according to claim 1, wherein each connection terminal holder has a first inside hollow portion, and wherein each of a plurality of connection terminals held at the predetermined position of the connection terminal holder in the electrically insulated state is constituted by a connection terminal body and a cap put on the connection terminal body with a gas passing hole between the cap and the heating element, and wherein a connection terminal inside hollow portion is formed between the cap and the connection terminal body, and wherein the connection terminal inside hollow portion communicates with the first inside hollow portion to which a gas introduction system for introducing gas is connected.
 7. A heating element CVD system according to claim 4, wherein as to the cap, a cylindrical body or a plate that covers the connection region of the heating element connected to the connection terminal without contacting the heating element and that is made of a insulating material or a metal or a composite material of these materials are mounted.
 8. A heating element CVD system according to claim 6, wherein as to the cap, a cylindrical body or a plate that covers the connection region of the heating element connected to the connection terminal without contacting the heating element and that is made of a insulating material or a metal or a composite material of these materials are mounted.
 9. A heating element CVD system according to claim 5, the gas is any one gas of hydrogen, argon, helium, neon, krypton, xenon, nitrogen, or ammonia, or a mixed gas of two or more kinds of these gases.
 10. A heating element CVD system according to claim 6, wherein the gas is any one gas of hydrogen, argon, helium, neon, krypton, xenon, nitrogen, or ammonia, or a mixed gas of two or more kinds of these gases.
 11. A heating element CVD system according to claim 7, wherein the gas is any one gas of hydrogen, argon, helium, neon, krypton, xenon, nitrogen, or ammonia, or a mixed gas of two or more kinds of these gases.
 12. A heating element CVD system according to claim 8, wherein the gas is any one gas of hydrogen, argon, helium, neon, krypton, xenon, nitrogen, or ammonia, or a mixed gas of two or more kinds of these gases.
 13. A heating element CVD system according to claim 1, wherein a connection part between the connection terminal and power supply mechanism, or the connection part between the connection terminal and the power supply mechanism and a wiring part for electrically connecting the connection terminals is built in the connection terminal holder.
 14. A heating element CVD system according to claim 5, wherein each connection terminal holder has the first inside hollow portion, and wherein a connection part between the connection terminal and power supply mechanism, or the connection part of the connection terminal and the power supply mechanism and a wiring part for electrically connecting the connection terminals is arranged in the first inside hollow portion.
 15. A heating element CVD system according to claim 6, wherein each connection terminal holder has the first inside hollow portion, and wherein a connection part between the connection terminal and power supply mechanism, or the connection part of the connection terminal and the power supply mechanism and a wiring part for electrically connecting the connection terminals is arranged in the first inside hollow portion.
 16. A heating element CVD system according to claim 1, wherein each connection terminal holder communicates with a space in the processing container only through a plurality of gas blowing holes made in the surface on the side in face with the substrate holder and has a second inside hollow portion connected to the raw material gas supply system.
 17. A heating element CVD system according to claim 1, wherein each connection terminal holder holds a plurality of heating elements in face with the substrate holder, and wherein the gap between at least one or more heating element of the plurality of heating elements and the connection terminal holder is different from the gap between the other heating element and the connection terminal holder.
 18. A heating element CVD system according to claim 1, wherein each connection terminal holder holds a plurality of heating elements in face with the substrate holder, and wherein the distances between the neighboring heating elements of the plurality of heating elements are different from each other in part.
 19. A heating element CVD system according to claim 1, wherein each connection terminal holder holds a plurality of heating elements in face with the substrate holder, and wherein the gap between at least one or more heating element of the plurality of heating elements and the connection terminal holder is different from the gap between the other heating element and the connection terminal holder, and wherein the distances between the neighboring heating elements of the plurality of heating elements are different from each other in part. 